Exit area control for jet engines



. bec. 1s, 1951 G. W. KALLAL EXIT AREA CONTROL FOR JET ENGINES 4 Sheets-Sheet l Filed March 20, 1948 Dec. 18, 1951 G. w. KALLAL.

EXIT AREA CONTROL FOR JET ENGINES 4 Sheets-Sheet 2 Filed March 20, 1948 FIG.

FIG. 6.

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G. W. KALLAL EXIT AREA CONTROL FOR JET ENGINES Dec. 18, 1951 4 Sheets-Sheet C5 Filed March 20, 1948 INVENTOR.

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Dec. 18, 1951 G. w. KALLAL.

EXIT AREA CONTROL FOR JET ENGINES 4 Sheets-Sheet 4 Filed March 20, 1948 ff ,HIS ATTORNEYS.

Patented Dec. 18, 191,51

EXIT AREA CONTROL FOR JET ENGINES George W. Kallal, Overland, Mo., assignor to McDonnell Aircraft Corporation, St. Louis, M0., p a corporation of Maryland Application March 20, 1948, Serial N o. 16,048 11 Claims. (Cl. 60-35.6)

This invention relates to jet engines and isI more particularly directed to a mechanism for controlling the exit or effective nozzle area of the jet engine.

The primary object of this invention is to provide a means for minutely controlling the erl'ective area of the exhaust nozzle of a jet engine.

Another object of the invention is to provide a structure embodying a plurality of tiltable members arranged substantially in the same general shape as the tailpiece that forms the exhaust nozzle of a jet engine, which members are rotatably adjustable so that the effective nozzle area. may be varied.

Still another object of the invention is to provide a means for preheating the fuel supplied to the jet engine or afterburner construction through a mechanism comprising a. plurality of tubular longitudinally extended members arranged generally in the form of the tailpiece for the afterburner or jet engine through which members the fuel is conducted for the purpose of preheating the fuel before introduction into the engine or afterburner and which also cools the members to prevent burning or undue warping thereof.

In the drawings:

Fig. 1 is a longitudinal section view of an engine incorporating the invention,

Fig. 2 is a longitudinal section view taken along the line 2 2 of Fig. 5 similar to Fig. 1 but with certain members in a different position,

3 is a section view taken substantially along the line 3 3 of Fig. 1,

Fig. 4 is a section view taken substantially along the line 4 4 of Fig. 1,

Fig. 5 is an enlarged end view locking toward the left of Fig. 1,

Fig. 6 is a section view taken substantially along the line 6 6 of Fig. 2,

Fig. 7 is a section view taken substantially along the line 1 1 of Fig. 2,

Fig. 8 is a longitudinal section view ofia modified form of the invention,

Fig. 9 is a section view taken substantially along the line 9 9 of Fig. 8,

Fig. 10 is a longitudinal section view similar to Fig. 8 but with the parts in different positions; and

Fig. 11 is a. section view taken substantially along the line I I I I of Fig. 10.

The structure embodying the invention comprises a tubular member I provided with a flange 2 that is engageable with the exhaust flange 3 of a turbo jet engine 4, the latter being schematically illustrated. The right-hand end of the tubular member I is contracted to form an exit nozzle 5. the effective area of which is to be controlled in order that the optimum power output may be developed by the turbo jet engine, it being well known in the art that the output of a turbo jet engine may be controlled by varying the effective area of the exhaust nozzle.

The instant device is capable of functioning as an afterburner or, with structural variations well known inthe art, it may perform as a ram jet engine when detached from the exhaust flange of the turbo jet engine. The primary function, however, of the device is to perform as an afterburner in order to augment the thrust of the turbo jet engine.

A diffuser cone 6 is supported in the lefthand end of the tubular member I, as viewed in Figs. 1 and 2, by means of a plurality of air foil struts 1 to provide an annular passageway 8 through which the exhaust gases of the turbo jet engine pass. A plurality of rotatably adjustable louvers, each of which consists of a longitudinally extended member Il, preferably elliptical in cross-section and provided with a tubular extension II of reduced diameter, is rotatably received in a suitable combination bearing and packing gland. well known in the art, in the diffuser cone 6. The louver members are disposed circumferentially about the afterburner` and form, when adjusted to the Fig. 4 position, a substantially closed tapered tubular member. The opposite ends of the louver members Ill are likewise provided with a tubular extension I2 of reduced diameter that is rotatably received in a manifold I3 in a suitable bearing and packing gland, the manifold being ring-shaped and having a modied air foil contour. This manifold is supported by a plurality of struts I4 secured to the nozzle end of the tubular member l by means of a fuel manifold 23 that surrounds the nozzle end of the tubular member I. The manifold 23 and struts I4 are interiorly connected and they are also connected by means of a conduit I5 to a suitable source of fuel that is supplied thereto by means of the pump I6 or other pressure producer.

Each of the tubular extensions II is provided with an arm Il connected to a spider or suitable wheel I8 by means of linkages I9. The wheel I8 has a gear 20 associated therewith that meshes with a gear 2I mounted on a shaft 22 that extends through one of the air fuel struts 'I and is then connected by suitable mechanism to a control at the pilot's station. Rotation of the louver members I about their longitudinal axes will vary the eiective area of the nozzle and when moved from their closed position, such as illustrated in Fig. 4, to their open position, as illustrated in Fig. 6, the engine output will be varied from maximum to minimum or any intermediate value. depending upon the degree of adjustment.

'I'he fuel that is supplied to the conduit I5 and thence through the struts I4 is preheated when passing through the hollow tubular louver members I0. The heating of the fuel cools the louver members to prevent their being warped or distorted. At the time the fuel reaches the lefthand end of the louver members, it is close to the flash point and then passes through the tubular extension II into suitable conduits 24 formed interiorly of the diffuser cone 6 and then through suitable discharge orifices 25 into the annular passageway 8 whereupon it mixes with the exhaust gases from the turbo jet engine in the diffuser chamber 26 where combustion commences, the initial combustion being provided by suitable ignition means (not shown) if necessary. The heating of the fuel in the louvers to near the flash point makes possible the employment of a much shorter combustion chamber, thereby shortening the over-all length of the tubular member. The combustion of the fuel is completed in the combustion chamber 21 whereupon the burned gases will be exhausted from the exit nozzle as is customary in the art, to thereby augment the turbo engine output or the thrust on the aircraft in which the device is installed when operating as a ram jet engine.

A modified afterburner and jet engine construction is illustrated in Figs. 8 through 11 in which a tubular member 30 is securable to the exhaust ange 3l of a turbo jet engine 32 schematically illustrated, the flange 3I cooperating with the flange 33 provided on the tubular member 30. A diffuser cone 34 is provided with a plurality of steps to form a succession of annular diffusion areas and is mounted in the left-hand end of the tubular member 3D by means of a plurality of air foil struts 35 similar in construction to members 1 described above. The diiuser cone forms the diiusing chamber 36 and an annular passage 31 through which the exhaust gases from the turbo jet engine pass into the diffusion chamber and thence into the combustion chamber 38 and are exhausted through the nozzle 39 formed at the right-hand end of the tubular member which consists of louvers 40. Each louver member 40 is rotatably supported in a suitable manifold 4I mounted on the outlet end of the tubular member 3D. Each of these louvers is constructed similarly to louvers I0 described above. The tubular extensions on the left-hand ends thereof. as viewed in Fig. l0, are rotatably mounted in the manifold 4I and the right-hand ends of the louver members are rotatably mounted in an air foil manifold 42 constructed similarly to the manifold I3 described above. The manifold 42 has a conduit 43 connected to a suitable source of fuel and a pump 44 forces the fuel into the manifold 42 and is thence conducted through the louvers into the manifold 4I and thence by means of a, plurality of conduits 45 to the left-hand end of the tubular member where each conduit is provided with a discharge orifice 46 so that the fuel may be discharged into the annular passageway 31 for mixing with the exhaust gases derived from the turbo jet engine. It is then burned to augment the thrust of the turbo jet engine or when the device is used as a ram jet engine disconnected from the turbo jet 4 to provide the thrust necessary to propel the vehicle to which the device is secured. The heating 0f the fuel provides the necessary cooling for each of the louver members 40 in the same manner as set forth above.

The exit area of the nozzle 39 is controlled by rotatably adjusting each of the louver members 40 about their longitudinal axes and a lever 50 is connected to each reduced diameter tubular extension provided on the left-hand end of the louvers. These levers are connected to a circumferential linkage 41 operatively connected to a rotating mechanism 48 subject to the control of the pilot. An arm 49 connects linkage 41 and mechanism 48 to thereby position the individual louver members from the full line position. as illustrated in Fig. 11, to the dotted line or to any intermediate position to thereby control the effective exit area of the nozzle 39.

Suitable packings (not shown) are provided at the parts II, I2 and corresponding parts in Figs. 8-11 to prevent loss of fuel at the points where the tubular extensions enter the manifolds.

What I claim is:

1. An exit area control for jet engines comprising a tubular member open at one end; a plurality of louvers disposed in said tubular member and extending through said open end; and means to rotate each of said louvers on its longitudinal axis so that the planes of each louver will stand at various angles to the longitudinal axis of the tubular member to thereby vary the area of said open end.

2. An exit area control for a jet engine comprising a tubular member having an open end whose area is to be varied; a plurality of louvers mounted in said tubular member and circumferentially arranged therein, eachl louver consisting of a longitudinally extended member substantially elliptical in cross-section; and means to adjust each louver by rotating it on its longitudinal axis to thereby vary the area of said open end.

3. An exit area control fora jet engine comprising a tubular member having an open end; a plurality of louvers circumferentially disposed about the open end of said tubular member and rotatably mounted thereon; means to introduce fuel into said tubular member through said louvers; and means to adjust the position of said louvers to vary the effective area of the open end of said tubular member.

4. An exit area control for a jet engine comprising a tubular member having an open end whose area is to be controlled; a plurality of tubular longitudinally extended louvers disposed about the open end of said tubular member and rotatably mounted thereon; means to introduce fuel into said tubular member through said louvers; and means to rotatably adjust each louver on its longitudinal axis to thereby vary the effective area of said open end.

5. An exit area control for a jet engine comprising a tubular member having an open end whose area is to be varied; a plurality of longitudinally extended louvers; means supported at each end of said tubular member to circumferentially dispose said louvers; means to rotatably support said louvers in said last mentioned means; and means to rotatably adjust each louver on its longitudinal axis to thereby vary the effective area of said open end.

6. A jet engine comprising a tubular member whose ends are open; a diffuser mounted in said member in one end thereof to provide an annular passageway; an annular fuel manifold supported on the tubular member at the other end thereof; a plurality of longitudinally ex tended hollow louvers having an elliptical crosssection and extending substantially coaxially of said tubular member, each of said louvers being rotatably mounted in said diffuser and in said manifold and being circumferentially arranged within said tubular member; means to force fuel through said manifold and through said louvers; means to introduce the fuel into said passageway; and means to rotatably adjust said louvers to thereby vary the area of the open end of said tubular member.

'7. A jet engine comprising a tubular member whose ends are open; a diffusing member arranged in one end of said tubular member to provide an annular passageway therein; a plurality of tubular elliptically sectioned longitudinally extended louvers supported on one end of said tubular member, one end cf each louver being rotatably supported in said diffuser; a manifold rotatably supporting the other end of said louvers and supported on the other end of `said tubular member; means to introduce fuel into said manifold and into said louvers; means to introduce fuel into said passageway from said louvers; and means to rotatably adjust each of said louvers about their longitudinal axes to thereby vary the effective area of the other open end of said tubular member.

8. A jet engine comprising a tubular member Whose ends are open; a diffusing member arranged in one end of said tubular member to provide an annular passageway therein; a plurality of tubular elliptically sectioned longitudinally extended louvers; means to rotatably support one end of each of said louvers about the other open end of said tubular member; a tubular ring shaped fuel manifold rotatably supporting the other end of said louvers; means to conduct fuel into said manifold and into said louvers; means to conduct fuel from said louvers into said passageway; and means to rotatably adjust each of said louvers to thereby vary the effective area of the open end of said tubular member.

9, A device for a jet engine comprising a tubular member, one end thereof constituting an exhaust nozzle; a plurality of substantially tubular elliptical members disposed about the periphery of said nozzle; means secured to said tubular member to support said plurality of longitudinally extended substantially elliptical tubular members about the periphery of said nozzle; and means to rotatably adjust each elliptical tubular member on its longitudinal axis to provide lateral openings between said mem bers to thereby vary the effective area of the nozzle` l0. A device for a jet, engine comprising a tubular member, one end thereof constituting an exhaust nozzle; a plurality of substantially tubular elliptical members disposed about the periphery of said nozzle; means to support said plurality of longitudinally extended tubular members elliptical in cross-section about the periphery of said nozzle; and means to rotatably adjust each tubular member on its longitudinal axis to provide lateral openings between said members to thereby vary the effective area of the exhaust nozzle.

11. A device for controlling the exit area of the exhaust nozzle for a jet engine comprising a plurality of longitudinally extended tubular members elliptical in cross-section; means secured to said jet engine in which each of said tubular members is rotatably supported, said members circumferentially disposed about said means in the exit area of the exhaust of said engine; and means to rotatably adjust each of said tubular members to provide lateral openings between said members to thereby vary the effective area of the nozzle.

GEORGE W. KALLAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS NumI er Name Date 157,526 Leggett Dec. 8, 1874 2,411,895 Poole Dec. 3, 1946 FOREIGN PATENTS Number Country Date 16,321 Great Britain Aug. 1, 1908 

